汶川抗震救灾的基础地理信息综合应急服务

在5.12汶川特大地震抗震救灾中,国家测绘部门设计和组织实施了以数据成果服务、专用系统服务和专题制图服务为核心的基础地珲信息综合应急服务.其是针对汶川震区地形特点和抗震救灾主体工作需求,快速整合和提供震区已有的基础测绘成果和最新遥感影像资料;快速搭建集震区海量数据集成管理为一体并具备3维影像浏览、对比分析等功能的专用地理信息系统,为灾情评估分析和重建规划研究提供地理空间数据集成展示和分析平台;应需地制作反映受灾范围、受灾程度、救灾响应、规划思路等的各类专题地图和地图集,有效地表达地震灾害的时空分布、重建规划布局等.     

沈阳市水资源分区及开发利用与保护对策研究

对沈阳市水资源概况及其开发利用中存在的问题作以阐述和分析,根据沈阳市社会经济发展规划,按照因地制宜、统筹兼顾的原则科学合理地进行水资源开发利用分区,同时考虑水资源开发利用特点,突出现有水源及后备水源保留区的划分.基于分区结果,提出主要分区水资源开发利用与保护的对策及建议.     

中国大陆科学钻探主孔榴辉岩类岩石退变质过程——对超高压变质地体隆升的启示

中国大陆科学钻探的实施，揭示了深俯冲陆壳的三维结构。超高压变质岩的岩相学详细观察，发现榴辉岩类岩石占0—2000米岩心的60％。大多数榴辉岩的原岩具有长期居留地壳的历史，但是分布在607～783米附近的石榴单斜辉石岩，在成因上与石榴橄榄岩关系密切。从矿物成分，岩石化学特征上看他们构成超镁铁-镁铁质的岩浆杂岩，是俯冲过程中，地幔物质加入于深俯冲的岩片并一起遭受超高压变质作用。榴辉岩质的片麻岩，部分相当于所谓的副片麻岩，在主孔也占一定的地位。实际是中酸性成分的火成岩超高压变质的产物。花岗质片麻岩有多种类型，根据其中所夹的角闪黑云片岩残留体看来大部分应属角闪黑云斜长片麻岩选择性部分熔融的产物。榴辉岩类的变质演化可分为3个阶段。第一阶段(M1约230—240Ma)是超高压变质的峰期，其证据是石榴石、绿辉石、金红石中均发现柯石英的微粒包裹物，石榴橄榄岩中的钛斜硅镁石是其超高压变质历史的见证。第二阶段(M2，226—219Ma)早期退变质阶段，超高压变质岩退变为高压榴辉岩相和角闪岩相岩石，冠状体和后成合晶的生长是此阶段的标志，这些特征性结构反应了岩石的不平衡和再平衡的历史，说明了超高压变质地体的快速隆升。后来(219～180Ma)超高压变质地体长期处于中下地壳，在流体影响下，榴辉岩质片麻岩退变成的黑云角闪斜长片麻岩及绿帘黑云(角闪)片麻岩，他们经选择性部分熔融或经超临界流体的K交代作用转变为黑云角闪二长片麻岩(即所谓正片麻岩)。其中多含有铈褐帘石，成分环带明显，La／Ce=0．42—0．72，且边沿均有绿帘石的边，代表后期叠加的绿帘钠长角闪岩相退变质。第三阶段(M3：170—180Ma)以糜棱岩和构造角砾岩的出现为特征，代表与二次隆升的脆韧性脆性变形的过渡，这些构造岩的基质普遍发育绿泥石、阳起石和方解石，说明了绿片岩相的退变质。所有上述3期的变质作用均与榴辉岩所经历的构造过程相关。显微结构分析可以揭示结晶作用和变形作用之间的相对时序。基于现今已发表的同位素年代学数据可以将苏鲁地区中生代不同阶段的变质作用与构造过程相互联系起来。CCSD主孔所见的变质演化和相关的变形事件对中国大陆中生代大陆动力学提供如下启示；可以肯定华北和杨子两个板块在三叠纪的碰撞(-240Ma)必然引起巨量地壳物质深俯冲至地幔深度，发生超高压变质。超高压变质岩的早期退变质是一个绝热隆升的过程，而后长期滞留中下地壳，发生部分熔融，接着引发进一步的隆升导致伸展体制，伴随以绿帘钠长角闪岩至绿片岩相的退变质。     

分区多步最短路径极值法多值多次反射波追踪

基于网格单元扩展的射线追踪算法,如:较为流行的有限差分解程函方程法和最短路径法均是建立在费马(最小走时)原理基础上的射线追踪算法,只能进行单值(最小走时)的多次反射波的追踪.然而当介质速度反差较大或存在复杂反射界面(如:常见的向斜、背斜、透镜体、塌陷构造等)时,将出现波前的自相缠绕(即蝴蝶结现象),相应的地震射线则为多...     

3-D P-wave velocity structure of the crust beneath the Loess Plateau and surrounding regions of China

The crustal P-wave velocity structure beneath the Loess Plateau and surrounding regions, which is a transition zone between the Tibetan Plateau and the Huabei and Huanan Blocks of China, was tomographically imaged for the first time down to the depth of 80 km. The seismic sources comprised both local and regional earthquakes and the reconstruction was accomplished using a newly developed simultaneous inversion procedure, which solves for both the earthquake hypocentres and the 3-D velocity field. Special features of the procedure include a modified shortest path algorithm for the bent ray tracing, an analytic Jacobian matrix for solution updating, and a damped, minimum norm, constrained non-linear solver based on a CG approach. The velocity structure obtained is more complex than previously thought. The lateral velocity variations are consistent with the U-shaped seismic ring structure but the vertical variations along the Fenwei seismic belt are consistent with the mechanism of the Mountain-Basin generalized system formation. The velocity images of Loess Plateau, the transition zone may help to build a geodynamic mechanism for inland China, to explain the formation of ground fissures so prevalent in the Loess Plateau.     

秩亏自由网平差及其通解

通过坐标转换将初始坐标系下的特解转换得到任意坐标系下的通解,研究了秩亏自由网基准转换的实质。结果表明,秩亏自由网平差最优解实质是基于近似值所确定的基准下的最优解,在实际应用中确定合适的基准是关键。以西安地区GPS沉降监测网为例,不同基准下秩亏解均为该基准下最优解,但只有顾及板块运动的基准才具有物理意义。     

测井约束的地震反演在鄂尔多斯盆地大牛地气田中的应用

有测井约束的地震反演技术是国内外油气储层预测的关键技术之一,本文介绍了储层预测中常用的反演方法,对地震反演技术在储层预测过程中的一些关键技术环节作了初步探讨,重点介绍了测井约束的地震反演方法在鄂尔多斯盆地储层预测中的应用情况,最后就反演结果作了初步的跟踪分析．关键词地震反演,地质统计反演,储层预测。     

非稳态相移法叠前深度偏移

介绍一种能够适应介质速度横向变化的非稳态相移算子及其叠前深度偏移方法．为了克服常规相移偏移算法中要求速度横向不变的缺点,出现了基于非稳态滤波器理论的非稳态相移算子,即PSPI算子、NSPS算子和SNPS算子,其中SNPS算子是将前二者结合起来的一种对称的非稳态相移算子,它比前二者具有更高的精度和稳定性．为了提高运算速度,基于非稳态相移算子的叠前深度偏移算法采取了分片均匀近似的策略,Marmousi模型的叠前深度偏移结果证明了该算法的可行性和有效性。     

Simultaneous elastic parameter inversion in 2-D/3-D TTI medium combined later arrival times

Traditional traveltime inversion for anisotropic medium is, in general, based on a “weak” assumption in the anisotropic property, which simplifies both the forward part (ray tracing is performed once only) and the inversion part (a linear inversion solver is possible). But for some real applications, a general (both “weak” and “strong”) anisotropic medium should be considered. In such cases, one has to develop a ray tracing algorithm to handle with the general (including “strong”) anisotropic medium and also to design a non-linear inversion solver for later tomography. Meanwhile, it is constructive to investigate how much the tomographic resolution can be improved by introducing the later arrivals. For this motivation, we incorporated our newly developed ray tracing algorithm (multistage irregular shortest-path method) for general anisotropic media with a non-linear inversion solver (a damped minimum norm, constrained least squares problem with a conjugate gradient approach) to formulate a non-linear inversion solver for anisotropic medium. This anisotropic traveltime inversion procedure is able to combine the later (reflected) arrival times. Both 2-D/3-D synthetic inversion experiments and comparison tests show that (1) the proposed anisotropic traveltime inversion scheme is able to recover the high contrast anomalies and (2) it is possible to improve the tomographic resolution by introducing the later (reflected) arrivals, but not as expected in the isotropic medium, because the different velocity (qP, qSV and qSH) sensitivities (or derivatives) respective to the different elastic parameters are not the same but are also dependent on the inclination angle.